Agricultural implement

ABSTRACT

A crop-treating device composed of an elongated fore-and-aft extending crop-treating implement and an implement carrier that bridges over the implement and has sides extending alongside the implement sides. Supporting couplers connect the carrier sides to the implement sides with the rear portion of the carrier being adapted for vertical movement for coupling and uncoupling to the implement.

United States Patent Rettig et a1.

[15] 3,645,074 Feb. 29, 1972 [54] AGRICULTURAL IMPLEMENT [72] Inventors:Vernon Eugene Rettig, Bondurant; John Edward Maust, Jr., Des Moines;Joseph John Shintlelar, Ottumwa, all of Iowa 73 Assignee: p resiggi nMoli ne, 1ll. 221 Filed: on. 26,1970

[21] Appl.No.: 83,751

[521 U,S.Cl..,..,,..,,.,...,,,...,...,,,.56/l4,6,56/DIG.9.214/5I5 [51 1Ill- (11.45/02 [58] Field ofScardt..,...............6/14.6, 2,1316. 9;214/515, 214/390, 396

[56] References Cited UNITED STATES PATENTS 2,401,183 5/1946 Pooletal...56/D1G.9 3,159,956 12/1964 Greenetal. ..56ID1G.9

3,425,194 2/1969 Stott et a1 ..56/DIG. 9

FOREIGN PATENTS 0R APPLICATIONS 1,069,416 11/1959 Germany ..56/D1G. 9

Primary ExaminerAntonio F. Guida Attorney-H. Vincent Harsha, Harold M.Knoth, William A. Murray, John M. Nolan, Raymond L. l-Iollister andJimmie R. Oaks [57] ABSTRACT A crop-treating device composed of anelongated fore-and-aft extending crop-treating implement and animplement carrier that bridges over the implement and has sidesextending alongside the implement sides. Supporting couplers connect thecarrier sides to the implement sides with the rear portion of thecarrier being adapted for vertical movement for coupling and uncouplingto the implement.

35 Claims, 11 Drawing Figures Patented Feb. 29, 1972 3,645,074

5 Sheets-Sheet 1 INVENTORS VERNON E. RETTIG, JOHN E. MAUST,JR. 8|

JOSEPH J. SHINDELAR Patented Feb. 29, 1972. 3,645,074

5 Sheets-Sheet 2 INVEN RS VER E. RET

JOHN AUST,JR. JOSE SHINDE Patented Feb. 29, 1972 3,45,074

5 Sheets-Sheet 5 FIG. 7

INVENTORS VERNON E. RETTIG, JOHN E. MAUST, JR. 8| JOSEPH J. SHINDELAR Pa t ented, Feb. 29, 1972 5 Sheets-Sheet 4 INVENTORS VERNON E. RETTIG,JOHN E. MAUST,JR. 8 JOSEPH J. SHINDELAR Patented Feb. 29, 1972 3,645,074

5 Sheets-Sheet 5 INVEN S VERNON E. RET

JOHN E. MAUST,JR. & JOSEPH J. SHINDELAR AGRICULTURAL IMPLEMENTBACKGROUND OF THE INVENTION It has heretofore been known to provide animplement carrier that is capable of supporting a variety of implementsthereon. The most basic type of such implements is a tractor which maybeadapted to carry any of several implements. In the carrier implementtype of harvesting device, there is normally provided a relatively smallcarrier or tractor with a com parativel'y low-capacitycrop-treating unitattached thereto. The implement is therefore of comparativelylightweight and the coupling and uncoupling of the implement from itsmain carrier is relatively simple. In most instances, the implement maybe attached by manual means and in some instances, hydraulic units areused to raise and lower the implement into aligned positions with thesupporting coupler members on the tractor or carrier.

When it is desired to have large capacity implements, it is, of course,necessary to have complementary large traction or carrier units. Themeans of detaching and attaching the implement on the carrier must alsobe somewhat complicated and there must be provided means for aligningthe supporting couplers between the implement and tractor as well as thedrive mechanism between the implement and't'ractor. Also, sincehigh-capacity implements require large material containers that receivethe treated crop, provision must also be made on the carrier forsupporting a large box or container thereon.

SUMMARY OF THE INVENTION With the above in mind, it is a primary objectof the present invention to provide an implement-carrier combination inwhich the implement may be detached from the carrier and, of course, thecarrier is capable of supporting one of many implements thereon.

Specifically, it is an object of the invention to provide an implementwith supporting stands that permit it to be supported on the ground. Theimplement has a relatively long, narrow lower section and acomparatively wide upper section that projects to opposite'sides of thelower section at the rear portion ofthe lower section. The carrier ortractor is supported on front and rear pairs of supporting wheels andhas a front transverse portion that overlies the front, narrow, lowersection on the implement and has depending portions that are positionedalongside the front portion of the implement and are connected at theirlower ends to the from supporting wheels. The depending portions arealso provided with coupling means that connect the front end of theimplement to the tractor.

The rear portion of the carrier or tractor is supported for verticalmovement on the rear support wheels. Rearwardly projectingandtransversely spaced-apart portions extend from the front transverseportion of the carrier in underlying rela-. tion to the outwardlyprojecting portions of the upper section ofthe implement. Downwardlyfacing coupling elements are provided on the implement and upwardlyfacing complementary coupler elements are provided on the rearwardlyprojecting portions of the carrier. Power means are provided between therear wheels and the rearwardly projecting porfions of the carrier toraise and'lower the portions and its coupler elements into and out ofcoupled and uncoupled positions with those on the implement.

It is still a further object of the present invention to provide a novelmeans for supporting the rear portions of the carrier on its supportwheels that includes an arm for each wheel carried on a horizontal pivoton the carrier. A hydraulic unit is provided for each arm and extendsbetween the carrier and arm. By extending and retracting the hydraulicunits, the carrier is raised and lowered on the respective wheels. Also,in operation, the cylinders may be used to ensure ground contact withthe rear wheels. This is important since it is desirable to have groundcontact to ensure proper steering, traction and weight-carryingcapabilities.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the carrier,implement and forwardly positioned harvesting unit.

FIG. 2 is a front left side perspective view of the implement shown onits supporting stands.

FIG. 3 is a side view of the carrier.

FIG. 4 is a rear perspective view looking into the carrier.

FIG. 5 is a plan view of the carrier.

FIG. 6 is a side view of the lower portion of the carrier with portionsremoved to show internal mechanisms and as taken substantiallyalong theline 66 of FIG. 4.

FIG. 7 is a vertical sectional view showing a portion of the drivemechanism and the coupling assembly for the drive mechanism between theimplement and its carrier.

FIG. 8 is a plan view of the supporting structure for one of the rearwheels and as taken substantially along the line 8-8 of FIG. 6.

FIGS. 9, l0 and 11 are schematic views of the implement and the carrierin their completely detached positions, their position just prior totheir being coupled together and in their coupled position. Portions ofthe structure are broken away to show the operation of internalmechanisms.

DESCRIPTION OF TI-IE PREFERRED EMBODIMENT Referring now to FIG. 1, inits completely assembled position, the implement carrier is composed ofa basic implement 10, an implement carrier 11 and a forwardly positionedcrop harvester device 12. The crop-treating implement 10 is composed ofa lower section 13, elongated in a fore-and-aft direction andcomparatively narrow as compared to an upper section 14, the latterhaving outwardly projecting portions 15, 16 extending to opposite sidesof the lower portion 13. The lower portion 13 has a front portion 17projecting forwardly of the upper section 14. In the present instance,the crop-treating implement is of a com-shelling type, details of whichare unimportant for the present, that is contained in the housing of thelower section 13. The upper section 14 is composed of a largegrain-receiving tank that receives shelled corn from the lower section13 by a conveyor device, indicated in its entirety by the referencenumeral 18. A discharge conveyor device, indicated by the referencenumeral 19, is provided for the purposes of discharging crop from thetank of the upper section 14. The implement 14 has from and rearretractable supporting stands 21, 22 respectively that may be lowered tosupport the implement on the ground, such being shown in FIG. 2. Theimplement l4 terminates at its forward end in an upright plate 23 thathas a centrally located crop inlet24 and a pair of upwardly projectinglugs 25 on its upper edge. The plate 23 and lugs 25 are insertable in arear portion of the implement 12 in a manner identical to that shown inUS. Pat. 3,270,489 to Rohwedder issued on Sept. 6, 1966 and reissued asRe. 26,512 and in a manner permitting the harvester to be mountedforwardly of and project outwardly of front support wheels 34, 35 of thecarrier. Reference may be had to that patent for showing the specificdetails of the connection between the plate 23 and the harvester 12. Theimplement 14 has its operating mechanism driven from a main input shaft26 extending transversely across the implement and having fixed at itsouter lefthandend a pulley 27 having internal teeth 28. As will laterbecome apparent, power is introduced into the implement through the maininput shaft 26.

The implement carrier or tractor 11 is composed of a body portion 30having a forward transverse portion 31 that bridges over the forwardportion 17 of the implement. Depending from the transverse portion 31 isa pair of vertical portions 32, 33 that are positioned inwardly of andconnected to front support wheels 34, 35. Extending rearwardly from thetransverse portion 31 is a pair of horizontal portions 36, 37 positionedto underlie the outwardly projecting portions I5, 16 of the implement.The rearwardly projecting portions 36, 37 also overlie a pair of reartransversely spaced wheels 38, 39. The carrier 11 has amain engine powersourceindicated in its location by the engine housing'40 and thevertical exhaust pipe 41. The engine 40 is just rearwardly of anoperator's station 42. The engine 40 has a belt drive, indicated onlypartially at 43, that extends downwardly to a pulley 44 on a transversedrive shaft 45 which is axially coextensive with the shaft 26 when theimplement is properly mounted on the carrier. The pulley is mounted torotate on the shaft 45 and is fixed at 46 to rotate with a sprocket hub47 concentric with the shaft 45 and having an outer surface journaled at48 on a support 49 fixed to the depending body portion 32. The hub 47has rigid therewith a sprocket 50. As may best be seen from viewing FIG.7, the shaft 45 is mounted to shift axially in the hub portion 47. Theshaft 45 carries a second sprocket 51 and a flanged collar 52 that isaxially shiftable on the shaft 45 to overlie the sprocket 51. The drivebetween the sprockets 50, 51 is accomplished by first shifting thesprocket 51 adjacent the sprocket 50 and wrapping a free length ofdouble chain 53 around the sprockets. The collar 52 is then shifted overboth the sprockets 50, 51 and the chain 53 is held in engagement withthe teeth of both sprockets 50, 51. In this manner, when the enginedrives the pulley 44, a rotation of the shaft 45 occurs. On the innerside of the shaft 45 is a gear 54 that is axially shiftable to mesh withthe teeth 28 on the implement pulley 27. Thus, when the two sprockets50, 51 are positioned to be driven, the gear 54 will be axially shiftedinto engagement with the teeth 28 on the implement input shaft 26.

As may be seen from viewing FIGS. 1 and 3-5, the transverse portions 30form with depending portions 32, 33 a downwardly opening space and withthe rearwardly projecting portions 36, 37 a rearwardly opening spacethrough which the lower portion 13 of the implement may extend. In itsfinal disposition, as seen in FIG. 1, the upper section of grain tank 14is directly rearwardly of the cab 30 and engine 40. The rearwardlyprojecting portions 36, 37 are provided with upwardly opening notches60, 61 on their upper sides. The notches 60, 61 flare outwardly andupwardly to make it easier to receive transversely inwardly projectingrods 62, 63 that are rigid with the sides of the implement and projectfrom opposite sides of the lower portion 13. The respective portions 36,37 are raised and lowered on respective rear traction wheels 38, 39which in turn are connected to the respective portions by means ofrearwardly projecting arms 64, 65 mounted on transverse horizontaltrunnions or pivots such as is indicated in dotted representation at 66in FIG. 6. The arms 64, 65 include vertical portions 67, 68 that havetheir lower ends supported directly on the wheel axles of the wheels 38,39 and fore-and-aft extending horizontal portions 69, 70. Extendingbetween the rearwardly projecting portions 36, 37 and the fore-and-aftextending portions 69, 70 respectively are hydraulic cylinders 72, 73.Suitable structural framework as at 75 is provided on the respectiveportions 36, 37 to support the cylinders 72, 73.

Supported on horizontal portions 69, 70 of the arms 64, 65 are verticalpivots 78 carrying horizontal steering levers 80. Extending between themidpoints of the levers 80 and their respective frameworks 75 are secondcylinders 82 respectively having their ram ends connected to verticalpivot pins 84 respectively on the levers, and their cylinder endsconnected to vertical pivots 85, 86 on the respective frameworks. Thevertical portions 67, 68 are connected to the horizontal rearwardlyprojecting portions 69, 70 by means of vertical trunnions, one of whichis shown at 87 on the right rear wheel 39, which permits the lowerportions 67, 68 and their respective wheels 38, 39 to steer relative tothe tractor. As may best be seen from viewing FlG. 4, the verticalportions 67, 68 are L- shaped and have laterally extending arms thatreach outwardly to the respective vertical trunnions.

On the upper side of the horizontal legs 89, 90 are upright pivotmembers 91, 92 that receive the rear ends of links 93, 94 that extendforwardly and are connected at 95, 96 to the innermost ends of thesteering levers 79, 80. As may therefore become clearly apparent, therespective rear wheels 38, 39 are turned by the extension and retractionof the extensible and retractable hydraulic links or cylinders 82. Also,raising and lowering of the rearwardly projecting portions 36, 37 of thehousing structure is accomplished by raising and lowering the portionson the respective rear wheels 38, 39 by extending and retracting theextensible and retractable links or hydraulic cylinders 71, 72. ltshould also become apparent that the purpose of raising and lowering theportions 36, 37 is to permit the tractor portion 11 to move rearwardlyunder the implement 10 while the portions 36, 37 are lowered and untilthe respective notches 60, 61 are beneath the lugs 62, 63, at which timethe cylinders 72, 73 may be extended and force the lugs 62, 63 into thenotches 61, 62.

The wheels 38, 39 are driven by individual hydrostatic motors 98, 99.Fluid lines are fed to the respective motors 98, 99 through passages,not shown, in the vertical portions 67, 68. The swivel joints 87 arealso a slip-type fluid manifold with a cap 100 fixed against movementand into which is connected a pair of hydraulic hoses 102, 103 (FIG. 8).The manifold permits the entire wheel structure 39 to swivel about itsupright axis while permitting the movement or flow of fluid into thehydrostatic motor 99.

Fixed to and projecting outwardly from opposite sides of the lowersection 13 of the crop-treating implement and adjacent its forward endsare downwardly opening V-shaped latch elements 105. Complementary to thelatch elements 105 and supported on the lower ends of the vertical sideportions 32, 33 are complementary latch means, indicated in theirentireties by the reference numerals 106. Each latch means 106 includesa forwardly directed extensible and retractable link or hydrauliccylinder 107 having its forward rod end connected to one leg of abellcrank 108 that is pivoted at 109 for fore and-aft movement. Thebellcrank has its forward end connected to a latch linkage that includesa vertical link 110 carrying an inwardly projecting latch pin 111 at itslower end and connected at its upper end to a fore-and-aft extendinglink 112. The link 112 is pivotally connected to the structural portion33. The bellcrank 108 has a small link 113 that connects to the links110, 112 at their pivotal connection. Fixed to the portion 33 at itsunderside and facing downwardly is a V- shaped cup 114 that is adaptedto receive the V-shaped latch 105. There is provided, as previouslymentioned, a latch means 106 on each of the depending portion 32, 33 ofthe tractor.

As may become clearly apparent from viewing FIG. 6, the forward end ofthe lower section 13 of the implement may be raised and lowered into itsmounted position by extending and retracting respectively the cylinder107. When the implement latches 105 and their respective forward ends ofthe implement are in their raised or transport position, the hydrauliccylinder 107 is extended to a point where the forward arm of thebellcrank 108 and the link 113 provides an overcenter lock to therebyhold the latch member 105 into engagement with the cup 114.

ln understanding the method of mounting the implement on the tractor,reference should be made to FIGS. 9, 10 and 11. The implement 10 issupported on stands 21, 22 and the tractor 11 is driven forwardly of theimplement. The rearwardly projecting portions 36, 37 are lowered byretracting the cylinders 72, 73 in the manner previously described.Also, the cylinders 107 are extended to cause the latches to be at aconsiderably lower level than the V-shaped latches 105 on the implement10. The tractor is backed into position so that the sides 36, 37underlie the outwardly projecting portions 15, 16 of the implement andso that the notches 60, 61 are directly beneath the lugs 62, 63 on theimplement. At substantially the same time, the forward portion of theimplement will be in proper position or so that the latch 105 is insubstantial vertical alignment with the latch rod 111. An operatorpositioned in the cab of the tractor can judge the correct position bynoticing how close the upper portion 14 of the implement is to theengine portion 40 of the tractor. When this occurs, the cylinders 72, 73may be extended to raise the portions 36, 37 and lock the lugs or rods62, 63 in the notches 60, 61. Likewise, the cylinders 107 may beextended to raise the rods Inn: MnA

111 into engagement with the latches 105 and from there upwardly untilthe latches engage the downwardly opening cups 114. ln-this position,the implement will be mounted on the tractor substantially as shown inFIG. 11. The tractor 11 and implement are then in a position to move inand connect to the harvesting unit 12 in the manner described in thepreviously referred to U.S. Pat. 3,270,489 and its Re. patent 26,512. itis also to be understood that suitable wear plates,

such as at 115 and 116 are provided lengthwise and on the inner sides ofthe portions 32, 33 and 36, 37 to guide the implement in its properposition. It should also be noted that upon the implement being in itsmounted position, the drive shaft 45 will be axially aligned with theimplement shaft 26 so that the coupling arrangement previously describedand shown in FIG. 7 may be engaged. Thus, the implement, tractor andharvester are ready to operate.

Another feature of this system is the ability to raise or lower the rearof the vehicle during field operation. This is convenient, and adesirable feature when operating up or down hill, inasmuch as thecombine threshing portion or harvesting mechanism, which is attached tothe propelling vehicle, can be more nearly maintained level which givesbetter efficiency of the combine shoe, thus reducing grain losses.

We claim:

1. A crop-handling implement comprising: an elongated fore-and-aftextending crop-treating implement; an implement carrier having front andrear transversely spaced wheels and a body structure composed of aforward transverse portion bridging over the forward portion of theimplement and a pair of depending portions positioned on opposite sidesof and closely adjacent the implement forward portion, the bodystructure further having a pair of rearwardly projectingportions'extending from the transverse portion alongside and outwardlyof the implement; means mounting the depending portions on the frontwheels; means mounting the rearwardly projecting portions on the rearwheels; and detachable supporting couplers between the dependingportions and the forward portion of the implement and between therearwardly projecting portions and the implement.

2. The structure as set forth in claim 1 further characterized by theimplement having an upper section rearwardly of the transverse portionof the implement carrier, the upper section having outwardly projectingportions overlying the rearwardly projecting portions of the carrier.

3. The structure as set forth in claim 1 in which the means mounting therearwardly projecting portions on the rear wheels are adjustable toselectively raise and lower the portions; and further characterized bythe detachable couplers between the rearwardly projecting portions andthe implement being in part downwardly facing coupler elements on theimplement and in part upwardly facing complementary coupler elements onthe respective rearwardly projecting portions, and said coupler elementsare engaged and disengaged when the rearwardly projecting portions areraised and lowered respectively.

4. The structure as set forth in claim 3 further characterized by theimplement having a transverse main driven shaft and the carrier having atransverse drive shaft transversely alignable with the driven shaft whenthe couplers are coupled, and an axially shiftable drive coupler meansfor coupling adjacent ends of the shafts.

5. The structure as set forth in claim 3 further characterized bysupporting stands for said implement for retaining the downwardly facingcoupler elements above the upwardly facing coupler elements to permitdetachment of the implement from the carrier.

6. The structure as set forth in claim 1 characterized by the meansmounting the rearwardly projecting, portions on the rear wheels being inthe form of arms mounted on the respective rearwardly extending portionsto swing vertically on horizontal axes and connected at their ends tothe respective wheels; and extensible and retractable motors extendingbetween the arms and the respective portions for raising and loweringthe latter on the wheels.

7. The structure as set forth in claim 6 in which the couplers betweenthe rearwardly extending portions and implement are separated upon therearwardly extending portions being lowered and are coupled upon theirbeing raised.

8. The structure as set forth in claim 6 in which the wheels areconnected to the respective arms by vertical trunnions that permit thewheels to swivel about a vertical axis, and further characterized bypower-steering mechanism forcing selective turning of the respectivewheels.

9. The structure as set forth in claim 8 in which the powersteeringmeans includes extensible and retractable hydraulic motors connected atone of their ends to the respective arms with means at the opposite endsfor connecting them to the respective wheels.

10. The structure as set forth in claim 1 characterized by the couplersbetween the depending portions and the implement are downwardly facingcoupler elements on the sides of the implement and complementaryvertically movable and upwardly facing coupler elements on the dependingportions; and power means on the depending portions for coupling of therespective coupler elements by raising the coupler elements on thedepending portions and uncoupling by lowering them.

11. A crop-handling implement comprising: a crop-treating implementhaving an elongated relatively narrow fore-and-aft extending lowersection and an upper section rigid with the lower section and havingoutwardly projecting portions extending to opposite sides of the lowersection, and the lower section having a forward portion extendingforwardly of the upper section; an implement carrier having front andrear transversely spaced wheels and a body structure composed of aforward transverse portion bridging over the implement forward portionand a pair of depending portions positioned on opposite sides of andclosely adjacent the implement forward portion, the body structurefurther having a pair of rearwardly projecting portions in underlyingrelation to the outwardly projecting portions of the implement; meansmounting the depending portions on the front wheels; means mounting therearwardly projecting portions for vertical movement on the rear wheels;and couplers between the depending portions and the forward portion ofthe implement and between the rearwardly projecting portions and theimplement, the latter being adapted for coupling and uncoupling uponraising the lowering respectively of the rearwardly projecting portions.

12. A crop-handling implement comprising: a crop-treating implementhaving an elongated relatively narrow fore-and-aft extending lowersection and an upper section rigid with the lower section and havingoutwardly projecting portions extending to opposite sides of the lowersection, and said lower section having a projecting forward portionextending forwardly of the upper section; implement supporting standsconnected to the implement for suspending it above ground level; animplement carrier having front and rear transversely spaced groundwheels and a body structure composed of a forward transverse portionbridging over the implement forward portion and a pair of dependingportions positioned on opposite sides of and closely adjacent theimplement forward portion, the body structure further having a pair ofrearwardly projecting portions extending alongside opposite sides of thelower section from the forward transverse portion and in underlyingrelation to the outwardly projecting portions of the upper section;means for raising and lowering the rearwardly projecting portions on theground wheels; and couplers between the depending portions and theforward portion of the implement and between the rearwardly projectingportion of the carrier and the implement, the latter being adapted forcoupling and uncoupling upon raising and lowering respectively of therearwardly projecting portions.

13. A crop-handling implement comprising: an elongated fore-and-aftextending crop-treating implement; an implement carrier having front andrear transversely spaced wheels and a body structure composed of atransverse portion bridging over the implement and portions rigid withthe transverse portion positioned on opposite sides of and closelyadjacent the implement; means for raising and lowering the latterportions on the ground wheels; and couplers between the portions and theimplement adapted for coupling and uncoupling upon raising and loweringrespectively of the portions.

14. A traction carrier for an implement composed of a main bodystructure having a forward transverse portion supported over a pair offorward transversely spaced wheels, a pair of transversely spacedportions depending from the transverse portion closely adjacent andinwardly of the respective wheels and a pair of rearwardly projectingportions extending from the forward portion in transversely spacedrelation and terminating above a pair of rear wheels, the dependingportions and the rearwardly extending portions forming with thetransverse portion downwardly opening and rearwardly opening alignedspaces respectively; means mounting the forward wheels on the respectivedepending portions; and means supporting the rearwardly projectingportions on each of the respective rear wheels composed of an armmounted at one of its ends of a transverse horizontal pivot carried bythe respective rearwardly projecting portions and connected at itsopposite end to the respective wheel, and power means between the armand rearwardly projecting portion for raising and lowering therespective portion on its respective wheel; and coupling means on therearwardly projecting portions for coupling and uncoupling to animplement.

15. A traction carrier for an implement composed of a main bodystructure having a forward transverse portion supported over a pair offorward transversely spaced wheels, a pair of transversely spacedportions depending from the transverse portion closely adjacent andinwardly of the respective wheels and a pair of rearwardly projectingportions extending from the forward portion in transversely spacedrelation and terminating above a pair of rear wheels, the dependingportions and the rearwardly extending portions forming with thetransverse portion downwardly opening and rearwardly opening alignedspaces respectively; means mounting the forward wheels on the respectivedepending portions; and means supporting the rearwardly projectingportions on the rear wheels for vertical adjustment thereon; power meansfor raising and lowering the portions on their wheels; and couplingmeans on the portions for coupling and uncoupling to an implement.

16. The structure as set forth in claim in which the coupling meansincludes upwardly facing coupler elements that may be moved intocoupling position upon raising of the portions and uncoupled uponlowering of the portions.

17. A traction carrier for an implement composed of a main bodystructure carried on supporting wheels and having a transverse portionand transversely spaced portions rigid with the transverse portiondefining a gap for receiving an implement; means supporting the portionson the wheels for selective vertical movement including power means forraising and lowering the portions on the wheels; and coupling means onthe portions for coupling and uncoupling to an implement in response toraising and lowering of the portions.

18. The structure as set forth in claim 17 in which the transverseportion is supported on forward transversely spaced wheels and thetransversely spaced portions project rearwardly from the transverseportion to ends that are adjacent transversely spaced rear wheels; andthe means for raising and lowering the portions are arms connected forvertical pivotal movement to the wheels and portions, and the powermeans are extensible and retractable hydraulic cylinders operativelyconnected to the arms and portions for angularly adjusting the arms.

19. The structure as set forth in claim 18 in which the wheels areconnected to the arms to turn on vertical axes and further characterizedfor power means for selectively turning the wheels.

20. A traction carrier for an implement composed of a main body andhaving front and rear pairs of transversely spaced wheels, the bodyincluding a forward transverse portion supported over the forwardwheels, and a pair of rigid sides extending from the transverse portiondownwardly and rearwardly and forming with the transverse portion adownwardly and rearwardly opening implement receiving space; anoperators station and main power source supported on the transverseportion; a drive extending from the power source to a transverse driveshaft supported in one of the sides and adapted for connection to animplement shaft inwardly of the sides; means supporting the rear portionof said sides on the respective rear wheels composed of an arm mountedat one of its ends on a transverse horizontal pivot carried by therespective side and connected at its opposite end to the respectivewheel; and power means between the arm and rearwardly projecting portionfor raising and lowering the respective portion on its respective wheel.

21. A crop-handling implement comprising: a crop-treating implementhaving an elongated relatively narrow fore-and-aft extending lowersection and an upper section rigid with the lower section and havingoutwardly projecting portions extending to opposite sides of the lowersection, and said lower section having a projecting forward portionextending forwardly of the rear section; an implement carrier havingfront and rear transversely spaced wheels and a body structure composedof a forward transverse portion bridging over the implement forwardportion and opposite transversely spaced sides extending downwardly andrearwardly closely adjacent opposite sides of the implement and inunderlying relation to the outwardly projecting portions of theimplement; means mounting the sides on the front wheels and the rearwheels for vertical movement relative thereto; and supporting couplersbetween the sides and the implement adapted for coupling and uncouplingupon vertical adjustment of the sides on the wheels.

22. A crop-handling implement comprising: a crop-treating implementhaving an elongated relatively narrow fore-and-aft extending lowersection and an upper section rigid with the lower section and havingoutwardly projecting portions extending to opposite sides of the lowersection, and said lower section having a projecting forward portionextending forwardly of the upper section; an implement carrier having awheel-supported body structure composed of a forward transverse portionbridging over the implement forward portion and opposite transverselyspaced sides extending downwardly and 1 rearwardly of the transverseportion and defining therewith a downwardly and rearwardly opening spacethrough which the lower section of the implement may extend with theoutwardly projecting portions being in overlying relation to the sides;and detachable couplers between the sides and the implement.

23. The structure as set forth in claim 22 characterized by the sidesbeing adjustably carried on the wheels of the carrier for verticalmovement and power means for vertically adjusting the sides; and inwhich the couplers include coupler elements facing downwardly on theimplement and complementary coupler elements facing upwardly on thesides in vertical alignment with implement coupler elements so thatcoupling and uncoupling may occur by raising and lowering the sides.

24. A crophandling implement comprising: an elongated fore-and-aftextending crop-treating implement having opposite sides; a pair ofdownwardly facing coupler elements on the sides; an implement carriercomposed of a main body having front and rear pairs of support wheelsand a forward transverse portion extending over the implement at itsforward end, the body further having a pair of transversely spaced sidesextending downwardly and rearwardly and forming with the transverseportion a downwardly and rearwardly opening space upwardly facing;coupler elements vertically aligned with the aforesaid coupler elementssupported on the carrier sides; means mounting the forward wheels on therespective carrier sides; and means supporting the implement sides oneach of the respective rear wheels composed of an arm mounted at one ofits ends on a horizontal pivot carried by the respective rearwardlyprojecting portion and connected at its opposite end to the respectivewheel, and power means between the arms and respective implement sidesfor raising and lowering the sides for coupling and uncoupling thevertically aligned coupler elements.

25. A crop-handling implement comprising: an elongated fore-and-aftextending crop-treating implement having a relatively narrow elongatedportion extending between front and rear ends and a wide upper portionprojecting to opposite sides of the elongated portion adjacent its rearend; an implement carrier having front and rear transversely spacedwheels and a body structure composed of a forward transverse portionbridging over the forward portion of the implement and a pair ofdepending portions positioned on opposite sides of and closely adjacentthe implement forward portion, the body structure further having a pairof rearwardly projecting portions extending from the transverse portionalongside and outwardly of the implement and beneath the upper portionof the implement; means mounting the depending portions on the frontwheels; means mounting the rearwardly projecting portions on the rearwheels; detachable supporting couplers between the depending portionsand the forward portion of the implement and between the rearwardlyprojecting portions and the implement; and a harvester detachablysupported on the front end of the implement and projecting forwardly ofthe front wheels.

26. A crop-handling implement comprising: an elongated fore-and-aftextending'crop-treating implement having front and rear ends; a cropreceptacle above, rigid with, and having outwardly projecting portionsextending to opposite sides of the implement and rearwardly of theforward end of the implement; an implement carrier having front and reartransversely spaced wheels and a body structure composed of a forwardtransverse portion bridging over the portion of the implement forwardlyof the receptacle and depending and rearwardly projecting portionspositioned on opposite sides of the implement and extending from thetransverse portion alongside and outwardly of the implement inunderlying relation to the outwardly projecting portions of thereceptacle; means mounting the depending and rearwardly projectingportions on the front and rear wheels; detachable supporting couplersbetween the implement and the'depending and rearwardly projectingportions; and a harvester detachably supported on the forward end of theimplement and projecting outwardly of and forwardly of the front wheels.

27. The structure as set forth in claim 26 characterized by the carrierhaving a main power source and a transverse horizontal drive shaft meansin one of its depending and rearwardly projecting portions; and theimplement has a transverse horizontal main drive shaft means axiallyalignable with the drive shaft means of the carrier when the detachablesupporting couplers are coupled; and a drive coupling between therespective drive shaft means.

28. The structure asset forth in claim 26 characterized by each of therearwardly projecting portions being supported on the respective rearwheels by an arm horizontally pivotally mounted at one end thereon andconnected at the opposite end to the wheel, and an extensible andretractable link extending between the rearwardly projecting portion andarm for raising and lowering the portion on the respective wheel.

29. The structure as set forth in claim 28 further characterized by eachof said rear wheels being swiveled about an upright axis on the arm andfurther characterized by a hydraulic cylinder having means at one endfor anchoring it to rear wardly projecting portions and means at theopposite end for anchoring it to the wheel whereby extension andretraction of the cylinders will steer the wheel.

30. The structure as set forth in claim 29 characterized by therespective rear wheels having individual hydrostatic drives and havingfluid-transferring joints at the respective vertical swivels fortransferring fluid to the respective drives at said joints.

31. A crop-handling machine comprising: a main frame having an elongatedfore-and-aft extending crop-treating device supported thereon; a pair ofsupport wheels supporting the forward end of the frame; a rearfpair ofsupport wheels; and means supporting a rear portion 0 the frame on therespective rear wheels, said latter means comprising an arm mounted atone of its ends on a horizontal pivot carried by the frame; and verticalpivot means connecting the respective arm to a respective rear wheel;first adjustable power means between the arms and frame for raising andlowering the frame; and second adjustable power means between the armsand wheels for steering the latter on the vertical pivot means.

32. The structure as set forth in claim 31 in which the first adjustablepower means is an extensible and retractable hydraulic motor connectedto the respective arms and frame.

33. The structure as set forth in claim 31 in which the secondadjustable power means is a hydraulic motor for each of said rear wheelswith a part thereof connected to the respective arm and a part thereofoperatively connected to the wheel for turning the latter.

34. The structure as set forth in claim 31 further characterized by eachof said rear wheels having its own hydraulically operatedindividualmotor for driving the wheel inwardly of and alongside the respectivewheel, said vertical pivot means includes a vertical trunnion having aslip-type fluid manifold permitting transfer of hydraulic fluid to andfrom the respective motor at said trunnion.

25. A crop-handling machine comprising: a main frame having an elongatedfore-and-aft extending crop-treating device supported thereon; a pair ofsupport wheels supporting the forward end of the frame; a relativelylong and heavy cropharvesting mechanism cantilevered forwardly of theframe and the front wheels and feeding into the crop-treating device; arear pair of support wheels; and means supporting a rear portion of theframe on the respective rear wheels, said latter means comprising an armmounted at one of its ends on a horizontal pivot carried by the frame;and vertical pivot means connecting the respective arm to a respectiverear wheel; first adjustable power means between the arms and frame forraising and lowering the frame; and second adjustable power meansbetween the arms and wheels for steering the latter on the verticalpivot means.

1. A crop-handling implement comprising: an elongated fore-andaftextending crop-treating implement; an implement carrier having front andrear transversely spaced wheels and a body structure composed of aforward transverse portion bridging over the forward portion of theimplement and a pair of depending portions positioned on opposite sidesof and closely adjacent the implement forward portion, the bodystructure further having a pair of rearwardly projecting portionsextending from the transverse portion alongside and outwardly of theimplement; means mounting the depending portions on the front wheels;means mounting the rearwardly projecting portions on the rear wheels;and detachable supporting couplers between the depending portions andthe forward portion of the implement and between the rearwardlyprojecting portions and the implement.
 2. The structure as set forth inclaim 1 further characterized by the implement having an upper sectionrearwardly of the transverse portion of the implement carrier, the uppersection having outwardly projecting portions overlying the rearwardlyprojecting portions of the carrier.
 3. The structure as set forth inclaim 1 in which the means mounting the rearwardly projecting portionson the rear wheels are adjustable to selectively raise and lower theportions; and further characterized by the detachable couplers betweenthe rearwardly projecting portions and the implement being in partdownwardly facing coupler elements on the implement and in part upwardlyfacing complementary coupler elements on the respective rearwardlyprojecting portions, and said coupler elements are engaged anddisengaged when the rearwardly projecting portions are raised andlowered respectively.
 4. The structure as set forth in claim 3 furthercharacterized by the implement having a transverse main driven shaft andthe carrier having a transverse drive shaft transversely alignable withthe driven shaft when the couplers are coupled, and an axially shiftabledrive coupler means for coupling adjacent ends of the shafts.
 5. Thestructure as set forth in claim 3 further characterized by supportingstands for said implement for retaining the downwardly facing couplerelements above the upwardly facing coupler elements to permit detachmentof the implement from the carrier.
 6. The structure as set forth inclaim 1 characterized by the means mounting the rearwardly projectingportions on the rear wheels being in the form of arms mounted on therespective rearwardly extending portions to swing vertically onhorizontal axes and connected at their ends to the respective wheels;and extensible and retractable motors extending between the arms and therespective portions for raising and lowering the latter on the wheels.7. The structure as set forth in claim 6 in which the couplers betweenthe rearwardly extending portions and implement are separated upon therearwardly extending portions being lowered and are coupled upon theirbeing raised.
 8. The structure as set forth in claim 6 in which thewheels are connected to the respective arms by vertical trunnions thatpermit the wheels to swivel about a vertical axis, and furthercharacterized by power-steering mechanism forcing selective turning ofthe respective wheels.
 9. The structure as set forth in claim 8 in whichthe power-steering means includes extensible and retractable hydraulicmotors connected at one of their ends to the respective arms with meansat the opposite ends for connecting them to the respective wheels. 10.The structure as set forth in claim 1 characterized by the couplersbetween the depending portions and the implement are downwardly facingcoupler elements on the sides of the implement and complementaryvertically movable and upwardly facing coupler elements on the dependingportions; and power means on the depending portions for coupling of therespective coupler elements by raising the coupler elements on thedepending portions and uncoupling by lowering them.
 11. A crop-handlingimplement comprising: a crop-treating implement having an elongatedrelatively narrow fore-and-aft extending lower section and an uppersection rigid with the lower section and having outwardly projectingportions extending to opposite sides of the lower section, and the lowersection having a forward portion extending forwardly of the uppersection; an implement carrier having front and rear transversely spacedwheels and a body structure composed of a forward transverse portionbridging over the implement forward portion and a pair of dependingportions positioned on opposite sides of and closely adjacent theimplement forward portion, the body structure further having a pair ofrearwardLy projecting portions in underlying relation to the outwardlyprojecting portions of the implement; means mounting the dependingportions on the front wheels; means mounting the rearwardly projectingportions for vertical movement on the rear wheels; and couplers betweenthe depending portions and the forward portion of the implement andbetween the rearwardly projecting portions and the implement, the latterbeing adapted for coupling and uncoupling upon raising the loweringrespectively of the rearwardly projecting portions.
 12. A crop-handlingimplement comprising: a crop-treating implement having an elongatedrelatively narrow fore-and-aft extending lower section and an uppersection rigid with the lower section and having outwardly projectingportions extending to opposite sides of the lower section, and saidlower section having a projecting forward portion extending forwardly ofthe upper section; implement supporting stands connected to theimplement for suspending it above ground level; an implement carrierhaving front and rear transversely spaced ground wheels and a bodystructure composed of a forward transverse portion bridging over theimplement forward portion and a pair of depending portions positioned onopposite sides of and closely adjacent the implement forward portion,the body structure further having a pair of rearwardly projectingportions extending alongside opposite sides of the lower section fromthe forward transverse portion and in underlying relation to theoutwardly projecting portions of the upper section; means for raisingand lowering the rearwardly projecting portions on the ground wheels;and couplers between the depending portions and the forward portion ofthe implement and between the rearwardly projecting portion of thecarrier and the implement, the latter being adapted for coupling anduncoupling upon raising and lowering respectively of the rearwardlyprojecting portions.
 13. A crop-handling implement comprising: anelongated fore-and-aft extending crop-treating implement; an implementcarrier having front and rear transversely spaced wheels and a bodystructure composed of a transverse portion bridging over the implementand portions rigid with the transverse portion positioned on oppositesides of and closely adjacent the implement; means for raising andlowering the latter portions on the ground wheels; and couplers betweenthe portions and the implement adapted for coupling and uncoupling uponraising and lowering respectively of the portions.
 14. A tractioncarrier for an implement composed of a main body structure having aforward transverse portion supported over a pair of forward transverselyspaced wheels, a pair of transversely spaced portions depending from thetransverse portion closely adjacent and inwardly of the respectivewheels and a pair of rearwardly projecting portions extending from theforward portion in transversely spaced relation and terminating above apair of rear wheels, the depending portions and the rearwardly extendingportions forming with the transverse portion downwardly opening andrearwardly opening aligned spaces respectively; means mounting theforward wheels on the respective depending portions; and meanssupporting the rearwardly projecting portions on each of the respectiverear wheels composed of an arm mounted at one of its ends of atransverse horizontal pivot carried by the respective rearwardlyprojecting portions and connected at its opposite end to the respectivewheel, and power means between the arm and rearwardly projecting portionfor raising and lowering the respective portion on its respective wheel;and coupling means on the rearwardly projecting portions for couplingand uncoupling to an implement.
 15. A traction carrier for an implementcomposed of a main body structure having a forward transverse portionsupported over a pair of forward transversely spaced wheels, a pair oftransversely spaced portions depending from the transverse portionclosely adjacent and inwardly of the respective wheels and a pair ofrearwardly projecting portions extending from the forward portion intransversely spaced relation and terminating above a pair of rearwheels, the depending portions and the rearwardly extending portionsforming with the transverse portion downwardly opening and rearwardlyopening aligned spaces respectively; means mounting the forward wheelson the respective depending portions; and means supporting therearwardly projecting portions on the rear wheels for verticaladjustment thereon; power means for raising and lowering the portions ontheir wheels; and coupling means on the portions for coupling anduncoupling to an implement.
 16. The structure as set forth in claim 15in which the coupling means includes upwardly facing coupler elementsthat may be moved into coupling position upon raising of the portionsand uncoupled upon lowering of the portions.
 17. A traction carrier foran implement composed of a main body structure carried on supportingwheels and having a transverse portion and transversely spaced portionsrigid with the transverse portion defining a gap for receiving animplement; means supporting the portions on the wheels for selectivevertical movement including power means for raising and lowering theportions on the wheels; and coupling means on the portions for couplingand uncoupling to an implement in response to raising and lowering ofthe portions.
 18. The structure as set forth in claim 17 in which thetransverse portion is supported on forward transversely spaced wheelsand the transversely spaced portions project rearwardly from thetransverse portion to ends that are adjacent transversely spaced rearwheels; and the means for raising and lowering the portions are armsconnected for vertical pivotal movement to the wheels and portions, andthe power means are extensible and retractable hydraulic cylindersoperatively connected to the arms and portions for angularly adjustingthe arms.
 19. The structure as set forth in claim 18 in which the wheelsare connected to the arms to turn on vertical axes and furthercharacterized for power means for selectively turning the wheels.
 20. Atraction carrier for an implement composed of a main body and havingfront and rear pairs of transversely spaced wheels, the body including aforward transverse portion supported over the forward wheels, and a pairof rigid sides extending from the transverse portion downwardly andrearwardly and forming with the transverse portion a downwardly andrearwardly opening implement receiving space; an operator''s station andmain power source supported on the transverse portion; a drive extendingfrom the power source to a transverse drive shaft supported in one ofthe sides and adapted for connection to an implement shaft inwardly ofthe sides; means supporting the rear portion of said sides on therespective rear wheels composed of an arm mounted at one of its ends ona transverse horizontal pivot carried by the respective side andconnected at its opposite end to the respective wheel; and power meansbetween the arm and rearwardly projecting portion for raising andlowering the respective portion on its respective wheel.
 21. Acrop-handling implement comprising: a crop-treating implement having anelongated relatively narrow fore-and-aft extending lower section and anupper section rigid with the lower section and having outwardlyprojecting portions extending to opposite sides of the lower section,and said lower section having a projecting forward portion extendingforwardly of the rear section; an implement carrier having front andrear transversely spaced wheels and a body structure composed of aforward transverse portion bridging over the implement forward portionand opposite transversely spaced sides extending downwardly andrearwardly closely adjacent opposite sides of the implement and inunderlying relation to the outwardly projecting portions of theimplement; means mounting the sides on the front wheels and the rEarwheels for vertical movement relative thereto; and supporting couplersbetween the sides and the implement adapted for coupling and uncouplingupon vertical adjustment of the sides on the wheels.
 22. A crop-handlingimplement comprising: a crop-treating implement having an elongatedrelatively narrow fore-and-aft extending lower section and an uppersection rigid with the lower section and having outwardly projectingportions extending to opposite sides of the lower section, and saidlower section having a projecting forward portion extending forwardly ofthe upper section; an implement carrier having a wheel-supported bodystructure composed of a forward transverse portion bridging over theimplement forward portion and opposite transversely spaced sidesextending downwardly and rearwardly of the transverse portion anddefining therewith a downwardly and rearwardly opening space throughwhich the lower section of the implement may extend with the outwardlyprojecting portions being in overlying relation to the sides; anddetachable couplers between the sides and the implement.
 23. Thestructure as set forth in claim 22 characterized by the sides beingadjustably carried on the wheels of the carrier for vertical movementand power means for vertically adjusting the sides; and in which thecouplers include coupler elements facing downwardly on the implement andcomplementary coupler elements facing upwardly on the sides in verticalalignment with implement coupler elements so that coupling anduncoupling may occur by raising and lowering the sides.
 24. Acrop-handling implement comprising: an elongated fore-and-aft extendingcrop-treating implement having opposite sides; a pair of downwardlyfacing coupler elements on the sides; an implement carrier composed of amain body having front and rear pairs of support wheels and a forwardtransverse portion extending over the implement at its forward end, thebody further having a pair of transversely spaced sides extendingdownwardly and rearwardly and forming with the transverse portion adownwardly and rearwardly opening space upwardly facing; couplerelements vertically aligned with the aforesaid coupler elementssupported on the carrier sides; means mounting the forward wheels on therespective carrier sides; and means supporting the implement sides oneach of the respective rear wheels composed of an arm mounted at one ofits ends on a horizontal pivot carried by the respective rearwardlyprojecting portion and connected at its opposite end to the respectivewheel, and power means between the arms and respective implement sidesfor raising and lowering the sides for coupling and uncoupling thevertically aligned coupler elements.
 25. A crop-handling implementcomprising: an elongated fore-and-aft extending crop-treating implementhaving a relatively narrow elongated portion extending between front andrear ends and a wide upper portion projecting to opposite sides of theelongated portion adjacent its rear end; an implement carrier havingfront and rear transversely spaced wheels and a body structure composedof a forward transverse portion bridging over the forward portion of theimplement and a pair of depending portions positioned on opposite sidesof and closely adjacent the implement forward portion, the bodystructure further having a pair of rearwardly projecting portionsextending from the transverse portion alongside and outwardly of theimplement and beneath the upper portion of the implement; means mountingthe depending portions on the front wheels; means mounting therearwardly projecting portions on the rear wheels; detachable supportingcouplers between the depending portions and the forward portion of theimplement and between the rearwardly projecting portions and theimplement; and a harvester detachably supported on the front end of theimplement and projecting forwardly of the front wheels.
 25. Acrop-handling machine comprising: a main frame having an elongatedfore-and-aft extending crop-treating device supported thereon; a pair ofsupport wheels supporting the forward end of the frame; a relativelylong and heavy crop-harvesting mechanism cantilevered forwardly of theframe and the front wheels and feeding into the crop-treating device; arear pair of support wheels; and means supporting a rear portion of theframe on the respective rear wheels, said latter means comprising an armmounted at one of its ends on a horizontal pivot carried by the frame;and vertical pivot means connecting the respective arm to a respectiverear wheel; first adjustable power means between the arms and frame forraising and lowering the frame; and second adjustable power meansbetween the arms and wheels for steering the latter on the verticalpivot means.
 26. A crop-handling implement comprising: an elongatedfore-and-aft extending crop-treating implemeNt having front and rearends; a crop receptacle above, rigid with, and having outwardlyprojecting portions extending to opposite sides of the implement andrearwardly of the forward end of the implement; an implement carrierhaving front and rear transversely spaced wheels and a body structurecomposed of a forward transverse portion bridging over the portion ofthe implement forwardly of the receptacle and depending and rearwardlyprojecting portions positioned on opposite sides of the implement andextending from the transverse portion alongside and outwardly of theimplement in underlying relation to the outwardly projecting portions ofthe receptacle; means mounting the depending and rearwardly projectingportions on the front and rear wheels; detachable supporting couplersbetween the implement and the depending and rearwardly projectingportions; and a harvester detachably supported on the forward end of theimplement and projecting outwardly of and forwardly of the front wheels.27. The structure as set forth in claim 26 characterized by the carrierhaving a main power source and a transverse horizontal drive shaft meansin one of its depending and rearwardly projecting portions; and theimplement has a transverse horizontal main drive shaft means axiallyalignable with the drive shaft means of the carrier when the detachablesupporting couplers are coupled; and a drive coupling between therespective drive shaft means.
 28. The structure as set forth in claim 26characterized by each of the rearwardly projecting portions beingsupported on the respective rear wheels by an arm horizontally pivotallymounted at one end thereon and connected at the opposite end to thewheel, and an extensible and retractable link extending between therearwardly projecting portion and arm for raising and lowering theportion on the respective wheel.
 29. The structure as set forth in claim28 further characterized by each of said rear wheels being swiveledabout an upright axis on the arm and further characterized by ahydraulic cylinder having means at one end for anchoring it torearwardly projecting portions and means at the opposite end foranchoring it to the wheel whereby extension and retraction of thecylinders will steer the wheel.
 30. The structure as set forth in claim29 characterized by the respective rear wheels having individualhydrostatic drives and having fluid-transferring joints at therespective vertical swivels for transferring fluid to the respectivedrives at said joints.
 31. A crop-handling machine comprising: a mainframe having an elongated fore-and-aft extending crop-treating devicesupported thereon; a pair of support wheels supporting the forward endof the frame; a rear pair of support wheels; and means supporting a rearportion of the frame on the respective rear wheels, said latter meanscomprising an arm mounted at one of its ends on a horizontal pivotcarried by the frame; and vertical pivot means connecting the respectivearm to a respective rear wheel; first adjustable power means between thearms and frame for raising and lowering the frame; and second adjustablepower means between the arms and wheels for steering the latter on thevertical pivot means.
 32. The structure as set forth in claim 31 inwhich the first adjustable power means is an extensible and retractablehydraulic motor connected to the respective arms and frame.
 33. Thestructure as set forth in claim 31 in which the second adjustable powermeans is a hydraulic motor for each of said rear wheels with a partthereof connected to the respective arm and a part thereof operativelyconnected to the wheel for turning the latter.
 34. The structure as setforth in claim 31 further characterized by each of said rear wheelshaving its own hydraulically operated individual motor for driving thewheel inwardly of and alongside the respective wheel, said verticalpivot means includes a vertical trunnion having a slip-type fluidmanifold permitting transfer of hydraulic fluid to And from therespective motor at said trunnion.